Imagine this: your son shows you a raised patch of skin on his chest. He says it doesn't really hurt, so you decide to see what happens and don't call the doctor. About a week later, the patch is joined by lots of smaller, oval-shaped spots. What's going on?
Chances are your son has a harmless condition called pityriasis rosea, which usually goes away on its own without treatment. Still, it's important to get it checked out by the doctor to make sure that's exactly what it is, and to rule out other unlikely conditions.
About Pityriasis Rosea
Pityriasis rosea (pit-ih-RI-uh-sis row-ZAY-uh) is a common skin rash in older kids and teens. It can appear anywhere on the body, but usually starts with one large, slightly raised patch of scaly skin on the chest, belly, back, or thighs.
As the rash spreads, the original patch is joined by a number of smaller spots that spread out across the torso. In some cases, the spots spread to the arms and legs. The spots can be slightly itchy.
Pityriasis rosea is not contagious. And once you've had it chances are you won't ever get it again. Although sometimes the spots can take a while to fade completely, most kids have no lingering traces of the rash after it's healed.
Doctors aren't really sure what causes pityriasis rosea. Some think it's caused by a virus, but this hasn't been proved. We do know that it's not caused by allergies, bacteria, or fungi.
While kids ages 10 and older and women are more likely to get pityriasis rosea, it can affect anyone of any age or skin color. It's also more likely to show up in the spring and fall.
Most kids and teens who get pityriasis rosea have no warning signs. Sometimes kids report having flu-like symptoms in the days leading up to an outbreak, although this is rare.
The rash itself typically starts with one large spot called a "mother" patch, or herald patch, that can appear anywhere on the skin but usually erupts on the chest, abdomen, back, or thighs. This patch can be raised and may feel scaly. In people with light skin, the patch is pink or red. People with darker skin can see a variety of colors, from violet to brown to gray.
The "mother" patch may be the only sign of this condition for up to 2 weeks. As the rash progresses, however, smaller spots can appear across the torso and on the arms and legs. They're usually symmetrical — so the spots will appear almost identical on both sides of the body. These small patches are sometimes called "daughter" patches. They're generally oval and smaller than the "mother" patch, and they often form a pattern on the back that resembles a Christmas tree.
Both the "mother" and "daughter" patches can be itchy and scaly. Some kids report feeling tired or rundown, or have flu-like symptoms that accompany the rash.
To diagnose pityriasis rosea, the doctor will examine your child's skin to look for the telltale signs of the rash. Sometimes doctors gently scrape off a few scales from the rash to examine under the microscope to rule out other possible causes, like ringworm or psoriasis.
Most cases of pityriasis rosea go away in 1 to 2 months without any treatment. Some cases can be as short as 2 weeks, while others can last for 3 months or longer.
When pityriasis rosea does require treatment, it's usually just to control the itching. Over-the-counter itch creams or allergy syrups can help, and so can oatmeal baths. Oral antihistamines also can reduce swelling and minimize itchiness.
Sometimes doctors prescribe creams or ointments that soothe the skin and decrease redness. Light therapy might be prescribed for cases where the itch is really bothersome. Usually, this involves ultraviolet B (UVB) therapy done by a dermatologist.
In some cases, just getting a moderate amount of sunlight can help treat the rash. If your child uses this form of light therapy, make sure he or she is protected from sunburn, which can sometimes make a rash worse.
Reviewed by: Kate M. Cronan, MD
Date reviewed: February 2012